Apparatus for investing and casting inlays



' Feb. 14, 1939. 'v-- W v 2,147,103

I APPARATUS FOR INVESTING AND CASTING INLAYS Filed Feb, 5, 1937 '-2Sheets-Shegt-l BY ATTORNEY Feb. 14,1939. E 2,147,103

APPARATUS FOR INVESTING AND CASTING INLAYS Filed Feb. 5, 1957 I 2Sheets-Sheet 2 ATTORNEY l Patented Feb; 14,1939

wan

My "invention relates to "a processjandapparatus forJinvestingandicasting-dentalinlaysf An ob jectof my' invention is to provide meansl iorlapplyingithe'jinvesting materlal aboutwax I denturei formationsbyJal uniform and maximum centrifugalaction. l I I l-Aufurther object ofmy'invention is toprovide means' for such investing fsoas-to provide aclosely homogeneously invested mass, with all of the air 10. pockets"andf-the' moisture properly excluded therefrom'by'such centrifugalaction? l V A further object of myfinventi'onis.to provide anyelectrical apparatus: which will apply such centrifugal action atitheproper rate and-which can be conveniently controllediu- .ja-.'A"furtherobject of my inventi'ontis. to provide meansv forcasting inlaysfrom;-.gold,-.gusing the I sameapparatus which is'used. for theinvesting Drocessj.

A 'further obj'ect of my 'inventionis'to provide adjustable 'meansto"cast .such gold: centrifugally,

' and to l-s'upplyzthe maximumqamount of.:centrif.'

' inlay. I

A'afurtheriobject of'my inventionis t o provide identical? means forinvesting iandi-casting in a.

device-which readily a'ccommodates itself :tovthe centrifugally thrownposition.

Afurther. object of my invention is 'toprovide 3Q; a'rotating supportwhich=rotates horizontallyand ause'san electric-motor'forfthe mostefllcient oper ation; and whichrotatirlg sup'portincl'udesmeans for:regulating the balanced length of either the investing or .the castingmethods. -22,

v A further object or my inventionlisto provide the above Lmentionedcharacteristicsf in a 'con-' struction which is" reasona'ble in costoflkmanu fa'ctureb 'With theserxand-otherobjects. in' View, myinventionconsists 'in"the construction, arrangement" andxcombination of "thevarious parts of my; de-

vice,. w'hereby'the objectscontemplated are; at tainedgas hereinaftermore fullyset forth, point" ed out in my claim; and illustrated intheaccom s pariying adrawingspinwhich: v

. -Figure '11 isla'side elevation oizthe apparatus used .forlcentrifugally.v investirignnd' c asting the ra ure-es is-a ironti vievvtofathmcentrifugally thrown.;receiving cup; i; 1

' gFigurieA is a sectionalvlewof the investinglcup I together/with theinlay-receiving member, 1 l f -Figure 5iis 1a sectional YiQW-z'ShOWiIlgthe gold inlays just. before Iormat1on thereof,:f r

threaded integirl extension 23.

Figure 6; is' an elevation of the" machlnefshow ing the position, ofthemembers during the investm Qperatiomand- Figure Tis'acorrespondingyiew' showing the casting operation. I

tis highly essential in the'formationof dental inlays,- first thattlie'packing of the investing material about the preliminary waximpressions be as close and-as"hoinogeneous as possible to eliminate airpockets orb moisture pockets? His 10 also extremely important that thegold inlay whi'chis made'in the-holl'ow-fiiold, beof maximumconcentration and density 'and that the same bemade1with-sharply'tdefined *formation' so that it '-:---I will proceedto showfin 'my invention-that' both of these results can be'obtained inthe same identical' machine without'resorting to a great deal ofunncessary labor. Furthermorefin order to provid the proper closelypacked investment, as well 20 as the inlay, I use the principle ofcentrifugal force; properly applied; to achieve this result. a In orderto obtain the maximum efiect desired; I useanelectric motor for thepurpose; Ihave'used tha character III to designate generally an-eleci '5tric motor which is positioned 'verticallyand'in cludesthe usualupwardly =ektending"vertical i 'shaft ll." 'I-he motor 40 is attached'to the -base I2; and the electric cord connection is shown at I I3passing iritof-thebasein the usual manner. 1 l A'rheostat is providedat-14, having three posithe cylindricalvertical member l8, and the roundhead machine-screw la provides means for tightening the member l8against the shaft H. Pass- 5 7 ing through the member 'IB- at 2I -is therod'Zll, Which- -is retained against--slidable m'otion by means of; thewing nut 22, which includes the A cylindrical balancing weight- 24'slidably receives the rod 20 0' and is locked therewith by means ot themachine screwv25: 'JI'heend of the rod 20 is threaded,-as at i ,26,whichthreadedportiori receives-thesquarenut. -21; which nut serves tohelp maintain the locked positioni oi the weight. n :The forward: end.of :the' 51 rodfis; threadedsasraatg-28; and loosely engaged'therewith-tiszthe bracket 29 having the arcuate side arms 30; A nut isprovided at 3|, which bears against a suitable washer 32, and 'a.further retainingamemberlgis vprovided at .33; Suflicient o spaceis leftbetween I the. member a 33 I and the washer 32'so' that the bracket 29is free to pivot? in .a-vertical planein either-direction," as indicated'by'th atarrows fl in fi'giirej li.Suspended-from the-outer ends oftheflarms '30 is-the' pair or "an-1740s.

ceived at 31 within the ends 35. The engagement 38, which are bent overand which are reat 31 is fairly loose for the reasons to be given.

Attached between the lower ends of the members 33, at 33, is thehorizontal member 33 which The first operation necessary in' forming'the inlay is to take the wax impression which is formed in thenecessary shape desired; and pack the investing material closelyaboutthe same. It..; is'also extremely important to force out all moisturewithin such investing material.

I have used the character 43 to represent the i cylindricalinvesting-receiving membeng which 111- cludes a further asbestos orother liner 44, which is also cylindrical. The investing cup isindicated by .the'character 45, which includes the substantiallyarcuatesides and the lowerportion 41, which is slightly beveled to fltwithinthe upper portionof the member 43. ,Asmall opening is provided at in thebottom, of the investing cup. .A further member 50 isprovided,

- having the conical-formation 5| into which is pressed a substantialamount of wax 52. A series of pins 53 which are attached. to the waxformations 54, are forced through thewax 52 with their outer'endsextending s i htlyabovethe surface pfthe wax asshownin Figures 4 and :6.The member 50 includes the upturned annular flange 55, which snuglyreceives the member 43 at the bottom thereof. I I

After the wax impressionsare formed to the V suitable shape desired,-they are fixed in'the member 50 asexplained and the member 50 isVattached to the member 43 through the. medium of the flange 55. ;Theinvesting material is then formed. e r v The investing materialisusually a plaster substance which is.mixed. with,water, and thenecessary amount is then packed into the upper cup 45 as shown inFigure4. Themember 43, which then carries the member 50, as well as the cup45, is then placed within the cylindrical cup 40 in themachine. Sincethe combined weight of the; investing material together with the othermembers is heavier thanin the casting process, the rod 20 can be moveduntil it abuts .against the pin, 4 I when the wing nut isagaintightened.

This-throws the weight 24 farther outward with respect to themachine,providing the proper balance. I i

i'l'he rheostat control 'isrthen thrownover to the position at, l5,whichis the slow speed position, since ,I have found that the best investing,speed is about 1200 R. P. M. The motor then" rotates atlthis speed, andduring such rotation the plastic investing material, which Ihaveindicated by the character 55, is uniformlyand efflciently thrownthrough the opening 43.

Figure 6 shows the position of the various mem-;

bers during the centrifugal action jimparted thereto, andthe cylindricalmember 40-, carrying the-various members, 'will'lie'directlyina'horivaontal axis.

The machine-is allowed to run.for a certain length of time and after allof the investing material 56 1s thrown through the opening 48, it isthen surrounding thewax impressions 54. During: the continued motion .ofthe motor,-the centrifugal action imp rted tends to paclrlthe in-'material ll very closely about the-1m terial and all of such unnecessaryelements are thus completely removed from the investing material.

i "The centrifugal proces s impartedby the electric' motor, packs theinvesting material so closely about the wax impressions that there areno air pockets formed, which is highly essential for perfect casting.

The excess liquid within the member 40 is easily removed bypivoting themember 40 upwardly,

allowing the" same to fallout by gravity.

After this process the machine is stopped and the cup 43, carrying theattendant members, is removed from the member 40.

Next, thecup 45 is removed from the member 43 and then the pins'53 arepulled out of the wax and the investing material 55, which is now in thelower member .43. The member 50 is then pulled out, leaving the conicalopening. This operation, of course, is performed after the substance 56has set properly, which can be hastened in any manner-wellknown in theart. The resultantstructure is as shown inFigure 5, and the member 43is-reversed as shown in thisflgure. There are now provided a series ofopenings 58, which were formerly occupied by the .pins 53. The member 43is then suitably heated until the wax impressions 54 are completelyevaporated through the openings 58. l The device is. now ready for; thegold-inlay forming operation; -'I'he member 43, containing the paster.55, is now heated to a-fairly substantial degree to maintain thetemperature within the casting openings. Asolid gold piece, such as59,.is now placed within the 'lower portion of the cone 5! and directlyabove the openings. 53. The gold 59 is heated by means of a blow torch,or any other well known means, until it reaches the melting point,and-after a sufficient heat is applied to maintainthe same in a fluidcondition for the necessary interval,the arrangement is then again putinto the cylindrical cup 40, and the rheostat controlis thrown over tothe position It, which -is thehigher speed position, and which rangesfrom approximately 2000 to 2400 R. P. M. During such centrifugal action,the fluid gold is thrown into theopenings- 58' and thence inwardly intothe hollow cores formed by the removal of the wax impressions 54. I

During the centrifugal action, the gold is closelypacked with a maximumeffect so that sharp impressions are formed, providing flawless inlays.After preliminary cooling, the substance 56 is removed together with theinner lining member 44, and the material is broken away about thedentures. The excess gold is scraped off close to the dentures, whichgold canbe remelted and draw the metal awayfrom the walls ofthecavities, etc. "By the application of the undiminished and constantcentrifugal force, however, during such 'contraction the gold is stillbeing forced against-the outlines of the hollow gold sothat in spiteof.contraction, a-perfectly'formed denture is obtained.

During the casting'operatiomsince the weight a of the member 43 islightened, the rod 2|! is passed, I 10 left, throws the weight 24inwardly thereby again effecting the proper balance between theweight,and the processed material andattachments.

through the member l8 u ntil thepin 42 abuts thereagainst. This movementof'the rod to the From observation of Figure 3, it will be noted thatbeforethe machine attains full speed, the

pivoting action about the rod 20,-as'indicated by the arrows 34, allowsthe material to be gradually carried into the functioning positionwithout any tendency of spilling or abrupt jerks, which would be presentif: the connection were'madefrigid, "I'he pivotal connectiondescribed'compensates for this and insures a uniform action: I

It will now be seenthat- I have provided, a proc ess and apparatus forinvesting and casting inlays which employs means forusing a uniform and[maximum centrifugal action, which provides" 1 II means for investingwhichinsures'a closely packed investing mass with all air pocketsand-moistureg excluded, which is electrically driven to insure the mosteflicient results, which employs" an identical device for both investingand casting inlays by centrifugal action, which during'the gold cast-"in'gxoperation insures the immediate passage of the molten gold tothefldenture pocket, thereby eliminating heat losses, whichincludesmeansfor readily attaining desired adjustments in the machine, and that Ihave provided a structure which 1 is simply constructed. j 1

Some changes may be made in the construction and arrangement of theparts of my invention without departing from the real spirit and purposeof my invention, and it is my intention to cover, by my claim anymodified forms of structure or use of mechanical equivalents, which maybereasonablyincluded within their scope.

I 'I'c'laimas myinvention:

Anapparatus' for investing and casting inlays comprising an electricmotor, an arm attached transversely to the motor shaft, a receivingmember attached at one-end of said arm, means receivable inysaidreceiving member for causing centrifugal action to imparted to investingor I casting material, including a wax form receiving member, a cupcontaining plastic investing material engaged with said member said cupincluding a bottom having an opening for causing said investing materialto be thrown therethrough and about the .wax forms by; such centrifugalaction, a conical memberfor securingvwax formsseparably attached to saidreceiving member, re-

moval of said conical mem'ber causing a conical depression to be formedin the investing material throwninto said .receivingmember, saidconicali depression adapted to receive a molten metal, said conicalmember including wax impressedthereon, pins passing through the waxandattached to said wax forms, removal of said pins forming hollow'passageways for transferring said molten metal to the hollow cavitiesformed by evaporation of the wax forms, said transverse I arm includinga counter-weight attached thereto,

meansfor regulating balanced adjustment of said arm, including pinsattached to the arm at established points regulating proper balancingfor 1 either, investing or casting operation.

DALE L. mm. I

